Liner assembly and method of using in solution mining



D. C. RUSE July 9, 1968 LINER ASSEMBLY AND METHOD OF USING IN SOLUTIONMINING EFFLUENT :'*"7

FIG. 3

' g EFFLUENT SOLVENT Filed Dec. 28, 1965 I/////////////////AM N FIG FIGJ

INVENTOR DOUGLAS C. RUSE SOLVENT FIG.4-

ATTORNEY S' United States Patent Ofice 3,391,962 Patented July 9, 19683,391,962 LINER ASSEMBLY AND METHOD OF USING IN SOLUTION MINING DouglasC. Ruse, Regina, Saskatchewan, Canada, assignor to Kalium ChemicalsLimited, Regina, Saskatchewan,

Canada, a corporation of Canada Filed Dec. 28, 1965, Ser. No. 516,946 4Claims. (Cl. 2995) ABSTRACT OF THE DISCLOSURE A liner conduit isattached to a resilient tube to provide a liner assembly useful toextend the effective length of a fluid-carrying conduit. The resilienttube has a relaxed diameter larger than the internal diameter of thefluid-carrying conduit. The resilient tube is stretched to reduce itsdiameter. The apparatus is then pushed through the fluid-carryingconduit until the liner conduitprotrudes a predetermined amount beyondthe downhole end of the fluid-carrying conduit. The resilient tube isthen released and allowed to expand in diameter thereby sealing theannulus between the liner and fluid-carrying conduits.

This invention relates to solvent extraction techniques. It morespecifically relates to precisely positioning the solvent injection andsolution withdrawal points in a solution mining cavity.

In the operation of a solution mining cavity, the precise positioning ofthe solvent injection and solution withdrawal points within the cavityis important. In the solution mining of sodium chloride or potassiumchloride, for example, the efiiciency of the operation is greatlyincreased when the solvent is introduced near the top of the cavity andsolution is withdrawn from near the bottom of the cavity. If roofcontrol is accomplished by maintaining an insoluble insulating layer,e.g., petroleum oil, floating on the top of the cavity solution, theinjection point should be located beneath this layer. Disturbance of theinsulating layer by turbulence caused by the injected solvent is therebyreduced. The withdrawal point is desirably located sufliciently abovethe cavity floor to avoid becoming clogged with insolubles which settleto the bottom of the cavity. Under certain specific conditions,particularly if it is desired to alter or correct the shape of asolution mining cavity it may be desirable to locate the injection pointat the bottom and/or the withdrawal point at the top of the cavity. Forexample, if the diameter of the bottom of the cavity is unduly large, itmay be desirable to locate the withdrawal point nearer the top of thecavity.

In a typical solution mining operation, one or more bore holes aredrilled to communicate with a subterranean formation which it is desiredto extract. This formation usually contains minerals which it is desiredto recover. A casing of slightly smaller external diameter than theinternal diameter of the bore hole is then disposed through the borehole. The casing normally terminates well above the depth at whichextraction is initiated. The annular space between the casing and thebore hole is desirably filled with cement, grout or equivalent inertmaterial. This inert material seals the annular space thereby protectingthe formations adjacent thereto from extraction. The thus cased borehole provides a conduit for fiuid flow between the earths surface andthe extractable formation.

When it is desired to introduce solvent and recover solution from adepth below the terminus of the casing, additional conduits may beprovided in the form of internal tubing. Alternatively, a liner may beprovided to extend the effective length of the conduit provided by thecasing. By tubing is meant a conduit of smaller diameter than the casingdisposed internal to the casing and extending from the earths surface.By liner is meant a conduit of smaller diameter than the casing disposedinternal to the casing but extending only part way up the casing. Aliner is usually suspended from the internal surface of the casing byfrictional pressure. This frictional pressure is desirably provided by apacking means which also seals the annulus between the casing and theliner. While the manipulation and positioning of tubing is a simplematter, the placement, positioning and removal of liners requiresspecialized and sophisticated handling techniques and equipment.

Several types of liner devices are available. A number of methods ofplacing these liners in an emplaced casing are familiar to the art. Manyof these devices and techniques satisfactorily seal the liner in anemplaced casing at the desired position or elevation. These devices andmethods all have certain shortcomings. According to the presentpractice, liners are run down casings attached to tubing. Packing cupsor expandable packers are provided in association with the liners.Positioning of the liner is desirably checked by a logging tool on awire line. After the liner is satisfactorily positioned, the tubing isdetached from the liner. If an expandable packer is used, it must beexpanded before the tubing can be detached from the liner. Thus, aconsiderable amount of time consuming manipulation is required to set aliner in a casing in accordance with present practice.

Summary of the invention The instant invention teaches an improved linerassembly and an improved method of positioning a liner within a casing.The hereindescribed method requires significantly less time than themethods previously known to the art. The liner assembly includes a linerconduit attached to a resilient tube. The diameter of the resilient tubeis chosen such that its relaxed external diameter is larger than theinternal diameter of the casing or other fluid-carrying conduit in whichthe assembly is intended to be emplaced. The liner assembly taught bythe instant invention can be set with a wire line thereby avoiding thenecessity of running tubing down the bore hole for this purpose. Alogging tool is conveniently run down the bore along with the linerassembly thereby avoiding a separate logging procedure.

Detailed description According to the instant invention, a liner isattached to one end of a resilient tube or conduit. The resilientconduit has a normal external diameter slightly larger than the internaldiameter of the casing. The resilient casing is adapted to be engaged bya stretching or tension producing means. In practice, the tensionproducing means is caused to engage the resilient conduit. The resilientconduit is stretched until it has an external diameter somewhat lessthan the internal diameter of the casing in which it is to be placed.The thus stretched resilient conduit is locked into stretched position.The liner assembly, i.e., the resilient conduit and the liner, islowered down the cased bore hole. The location of the liner isdetermined by wire line measurement or by means of a logging tool. Whenthe liner is properly positioned, that is, when the free or terminal endof the liner is located at the desired elevation in the cavity, anelectrically or mechanically actuated mechanism releases the stretchingmeans thereby allowing the extended resilient conduit to relax and gripthe inside surface of the casing. The relaxed conduit fills the annularcross-section between the liner and the casing thereby functioning as apacker. Thus, the instant invention provides a more ex- 3 pedientequivalent of the expandable packers preferred by the prior art.

The instant invention will be more readily understood by reference tothe accompanying drawings of which FIGURE 1 illustrates the novel linerdevice of this invention in relaxed position. FIGURE 2 illustrates thesame device in stretched position. FIGURE 3 illustrates the use of thedevice in a solution mining cavity communicating with a single borehole. FIGURE 4 illustrates an application of the device in an embodimentwherein a large solution mining cavity communicates with two bore holes.

Referring to FIGURE 1, the liner assembly comprises a resilient conduitor tube 1 and a liner 2. The resilient conduit 1 is adapted to beengageable by a stretching means. One convenient device to adapt theresilient conduit for gripping by the stretching means is a ring, 3, 4or any equivalent which provides a shoulder or similar projectioninternal to the conduit. In some embodiments, the stretching means (orsetting tool) is adapted to grip the internal surface of the resilientconduit. In these embodiments, no diameter reducing shoulder isrequired. The liner 2 may be of any convenient material such as metal,plastic or fiberglass pipe or tubing. In the drawings, the liner isshown as threaded into ring 4 at the end of the resilient conduitalthough any convenient method of fastening the liner to the resilientconduit is within contemplation.

Any resilient extendable material of sufficient strength which isresistant to the solvent and other fluids with which it will be incontact in use may be employed. For example, in solution mining adeposit consisting essentially of sodium and potassium chlorides,As-inch neoprene has been found to be a suitable resilient material forplacing a liner in a 7-inch casing. FIGURE 2 shows the same assembly asis shown in FIGURE 1 with the resilient tubing extended in preparationfor insertion down a casing. To prepare the liner assembly forinsertion, the resilient tube is stretched over a setting tool 10. Instretched or extended position, the external diameter of the resilientconduit is reduced to less than the internal diameter of the casing. Thesetting tool 10- is conveniently attached to a Wire line 11. The settingtool 10 illustrated increases in length in response to tension in thewire line thereby stretching the resilient conduit. The gripping arms 13collapse or extend in response to electrical impulses carried down thewire line. In other embodiments, the length of the setting tool is fixedand the resilient conduit is stretched by independent means to engagethe tool. The tool is adapted to release the resilient conduit inresponse to an above ground manipulation.

Resilient conduits and stretching tools known to the art are employablein the instant invention. Any setting tool capable of being activatedfrom the earths surface to grip or release the resilient conduit of thisinvention is employable. Because such tools are well known, they are notdescribed in detail herein. U.S. Patent 3,067,819, for example,describes a casing interliner suitable for use as a resilient conduit inthe practice of the instant invention. Any of the several interlinersand stretching mechanisms disclosed in U.S. Patent 3,067,819, thedisclosure of which is hereby incorporated by reference, may be adaptedto be useful in the practice of the instant invention.

A typical application of the novel apparatus of this invention isillustrated by FIGURES 3 and 4. Referring to FIGURE 3, bore hole 5 isestablished to terminate at the depth at which extraction is tocommence. Casing 6 is disposed through bore hole 5 and terminates nearthe top of the extractable deposit, well above the bottom of the borehole. A liner assembly, with the resilient conduit extended over asetting tool 10, is introduced down casing 6 by means of a wire line 11(see FIGURE 2). The location of the assembly and thereby the elevationof the terminus or free end of the liner is readily 4 determined by alogging tool or by wire line measurement. The assembly is located sothat the terminus of the liner is close to the bottom of the bore hole.In this fashion, the effective length of the casing is extended toprovide a continuous conduit from the bottom of the bore hole 5 to theearths surface.

After the liner assembly is in place, tubing 7 is run down the bore holeand through the resilient tube andthe liner to terminate near the bottomof the bore hole. Oil is introduced down either the tubing or theannulus along with solvent. The oil floats on top of the solvent to forma protective layer 8 at the top of the bore hole. The oil also seals anyspace between the liner or the casing and the bore hole. Solvent is thencontinuously introduced and solution withdrawn to develop a cavity 9.The oil pad prevents uncontrolled vertical extraction and encourages thecavity to develop literally. Of course, other inert fluids lighter thanthe solvent may he used in lieu of oil.

After a cavity has developed sufficiently in size, it often is broughtinto communication with a second bore hole 15, as illustrated in FIGURE4. The internal tubing 7 is then removed from both communicating boreholes 5, 15. Liner assemblies are then introduced into each casing 6,16. Liner 2 functions as the input conduit while liner 12 functions asthe efiiuent conduit.

Whether a solution mining cavity communicates with a single or pluralityof cased bore holes, the effective length of the emplaced conduits,e.g., the cased bore holes, may need to be adjusted from time to time asthe cavity develops in size. Thus, it is often necessary to raise theterminus of the influent conduit to provide an injection point close tothe roof of the cavity. Similarly, it may be desired to reduce theeffective length of the effluent or withdrawal conduit so that thewithdrawal point will be sufliciently above the cavity floor to avoidbecoming clogged with insolubles. It may be desired to either raise orlower the injection and/or withdrawal point to establish a preferredflow pattern of the cavity solution. The effective length of a conduitmay be readily adjusted from time to time by reintroducing the settingtool 10, activating it to engage the resilient conduit, stretching theresilient conduit, relocating the'liner assembly at the desiredelevation and disengaging the setting tool to allow the resilientconduit to again set in the casing.

Although this invention has been described with primary reference tosolution mining, it may have other applications in related areas whereit is desired to precisely locate or relocate a fluid introduction orwithdrawal point in a subterranean cavity. The apparatus and methodherein described are useful in altering the effective length of anyconduit and are not limited in application to a casing cemented orotherwise sealed to a formation. It is not intended to limit the claimsto the specific details referred to in the description of this inventionexcept insofar as those details are included in the appended claims.

I claim:

1. A method of extending the effective length of a fluid carryingconduit communicating with a subterranean cavity to terminate at adesired elevation which comprises releasably stretching with anindependent stretching means a resilient conduit with normal externaldiameter greater than the internal diameter of said first named conduitto reduce the external diameter of said resilient conduit to less thanthe internal diameter of said first named conduit, said resilientconduit being attached to a liner conduit with external diameter smallerthan the internal diameter of said first named conduit, locating saidmeans and the stretched resilient conduit within said first namedconduit such that the terminus of said liner conduit is located at thedesired elevation and while the liner conduit is so positioned releasingthe stretching means to permit the resilient conduit to return towardits normal diameter thereby to engage the first named conduit.

2. The method of claim 1 wherein the first named fluid carrying conduitis a cased bore hole and the subterranean cavity is located in anextractable deposit.

3. The method of claim 1 wherein after the liner is first set at adesired elevation in the first named conduit a stretching means isintroduced down said first named conduit, the resilient conduit isreengaged and restretched by said stretching means so that its externaldiameter is again reduced to be smaller than the internal diameter ofsaid first named casing, the liner conduit is relocated at a seconddesired elevation and the stretching means is again released to allowthe resilient conduit to return toward its normal diameter therebyresetting the liner conduit at said second desired elevation.

4. An apparatus for extending the effective length of a fluid carryingconduit to terminate at any desired elevation in a subterranean cavitycomprising a resilient tube having a normal diameter larger than theinternal diameter of said conduit, means operably associated with saidresilient tube and arranged to be engaged by a tension producing means,a liner conduit attached to one end of said resilient tube and orientedto extend from said resilient tube and beyond the engageable means, saidresilient tube and liner conduit being constructed so that they arecapable of movement up or down in said fluid carrying conduit afterbeing set in one position therein to permit them to be set in a secondposition.

References Cited UNITED STATES PATENTS 385,600 7/1888 Durbrow 175 42zx2,745,647 5/1956 Gilmore 299 5 3,022,986 2/1962 Brandt 299-5 3,067,81912/1962 Gore 16614X 3,152,643 10/1964 Burns 166--208 X 20 ERNEST R.PURSER, Primary Examiner.

